This invention relates to the suppression of dust in the coal mining industry, and, more particularly, in mines wherein powered support units are utilized.
The dust suppression in the mines of the hard coal mining industry which use powered supports is burdened with difficulties. For example, in addition to the dust that is normally generated during mining operations, which can be considerably reduced by means of the well known soaking or jet blasting of the coal face, further amounts of dust are generated by the use of the support units themselves. This is caused, on the one hand, by the crushing of the lowest strata of the hanging wall or ceilings due to the high pressure of the support shields, and, furthermore, by the breaking down of the backfilling as the support shields advance.
One process for reducing the dust generated in powered advancing longwall mining, is to cover the hanging wall with plastic sheeting. In this process, the sheets are applied with the aid of the extraction or mining equipment and are pressed against the hanging wall with the aid of the mine supports. It is customary, in this regard, to arrange the sheets in the form of rolls placed in mounts attached to the support units so that as the extraction units advance, the sheets unroll. However, the mounts which are attached to the support units and which contain the sheet rolls are relatively bulky, resulting in a considerable disadvantage when dealing with seams of limited richness or thickness.